This is a photo of my local church taken when I was staying in a studio apartment in the 5th arrondissement for a month last year (2012). I was happily engaged in researching wheelchair/mobility accessible hotels, monuments, museums **and** transportation. I currently recommend Bus lines 38, 21 and perhaps 24 and 96 to arrive at Notre Dame de Paris. For line 38, descend (the French use the word “descendre” meaning to get off the bus, or escalator, etc.) at either “St. Michel-St. Germain” or “Cité-Palais du Justice“. To get to the Cathedral from either stop you should simply look up, look left, look right and then walk/roll toward Notre Dame. It’s amazingly right there!